This invention relates to an automatic detection technology by which an external device, such as adaptor card and a drive unit, can be preferably connected to an information processing apparatus, such as a computer system, and in particular to an automatic detection technology for identifying a connected external device and detecting a connection failure. More specifically, the present invention pertains to an automatic detection technology employing a minimum number of pins in a connector to detect a connection failure and to identify an external device.
In accordance with recent technological developments, various types of computer systems, such as desktops, towers and notebook, have been produced and are being sold. In particular, as the costs of components have been reduced because of the availability of enhanced semiconductor technology, general-purpose personal computers (PCs) designed for ordinary users have become popular.
As well known, a computer system comprises a main system which includes a CPU and a memory, and a plurality of subsystems, such as a video subsystem, a storage subsystem and a network subsystem. The main system is constituted by main circuit components, such as a CPU and a memory, and these components are generally mounted on a printed board called a planar or a motherboard.
As is well known to those having ordinary skill in the art, there are a plurality of subsystem types having different specifications and standards. For example, a plurality of types of video subsystems, such as a standard video subsystem and an enhanced video subsystem, are produced in accordance with specific resolutions and functions.
If the planar includes subsystems as its components, the planar must be designed again each time one of the subsystems is re-designed. Or, a plurality of planars must be prepared equivalent to the number of possible combinations of subsystems. This deteriorates the production efficiency and makes it difficult to cope with model renewal promptly. Therefore, at present, the subsystems are provided in the form of cards apart from the planar so that the cards can be detached/replaced.
The subsystems are provided for a system planar as adaptor cards, such as a video adaptor, a LAN adaptor and a SCSI (Small Computer System Interface) adaptor. The subsystems can also be provided as drive units, such as a hard disk drive (HDD), a floppy disk drive (FDD) and a CD-ROM drive. Connectors for electrically connecting these cards or drive units are provided on the planar to facilitate the detachment and replacement of the subsystems. A video card, such as xe2x80x9ccyber9320,xe2x80x9d xe2x80x9ccyber9385xe2x80x9d or xe2x80x9ccyber9385+H/W MPEG,xe2x80x9d is detachably connected to a video subsystem connector. A CD-ROM drive and a DVD drive, for example, are detachably connected to a storage subsystem connector. These connectors generally have an oblong structure in which signal pins are arranged in one direction.
When a plurality of devices are detachably connected to one connector, a mechanism for diagnosing connection problems and a mechanism for identifying connected devices are required to ensure the normal operation of the system and the smooth utilization of the devices. The mechanism for diagnosing the connection can perform a diagnostics program and can easily determine whether the cause of a malfunction is a connection failure. Since an alarm can be issued to a user instantaneously and directly, especially for an apparatus, such as an FDD or a CD-ROM drive, that a user manually handles, such mechanisms are very effective.
Furthermore, the identification mechanism can automatically identify the types of subsystems that are currently installed by the execution of certain firmware. Therefore, system configuration data can be automatically reconfigured, and a so-called PnP (plug-and-play) function can be implemented. Even during the power saving state when a suspended system is not completely powered off, replacement of subsystems is possible (for example, an FDD can be replaced by a CD-ROM drive).
FIG. 3 shows an example identification mechanism for a subsystem. In FIG. 3, three pins in a connector that electrically connects a subsystem to a planar are assigned to identification (ID) pins (ID0, ID1 and ID2). In the subsystem, identification information for the subsystem can be specified by either grounding the ID pins or by setting them in the opened state. An ID controller (tentatively named) on the planar can accept an identification signal obtained by pulling up the ID signals using a power voltage Vcc, and thereby read identification information for the subsystem. According to the example depicted in FIG. 3, since the identification information is expressed using three bits, a maximum of eight different subsystems (precisely, seven types, excluding an ID value indicating a connection failure, which will be described later) can be identified.
The subsystem depicted in FIG. 3 has the identification information (ID0, ID1, ID2)=(1, 0, 0). The ID controller reads (1, 0, 0), i.e., identification number 1 (=2xc2x0 C.), and specifies the name of the device currently employed as a subsystem. When a connection failure occurs at a connector, the ID pins are set in the opened state, i.e., go high. In this case, the ID controller obtains the identification information (ID2, ID1, ID0)=(1, 1, 1), i.e., ID value 7, and detects a connection failure.
According to the example depicted in FIG. 3, the identification mechanism for the planar and a single subsystem is shown. When the planar permits connections with multiple subsystems, the number of subsystem connectors on the planar is increased, and the number of ID signals is accordingly increased in proportion.
FIG. 4 shows an example where a planar permits the connection of three subsystems A, B and C. When the subsystem connectors each employ three ID pins, a total of nine ID pins are required, and an ID controller requires an ID signal having a 9-bit width. However, since the number of input pins for the ID controller is limited, it is difficult to assign dedicated ID pins for all the subsystems.
As was previously described, the connector has an oblong structure in which connector pins are arranged in one direction. With this structure, the connection failure shown in FIG. 5 occurs frequently as the result of an unskillful, diagonal insertion of a connector. However, in the arrangement wherein ID pins that are also employed for the detection of a connection failure are concentrated at one location (e.g. the center of the connector in FIG. 5) in the longitudinal direction of the connector, so long as the connection at that location is correct the identification number can still be read, and a connection failure will not be detected.
It is, therefore, one object of the present invention to provide a superior automatic detection technology for the preferable connection of external devices, such as an adaptor card and a drive unit, with the main body of an information processing apparatus, such as a computer system.
It is another object of the present invention to provide a superior automatic detection technology for identifying external devices mounted, and for detecting a connection failure.
It is an additional object of the present invention to provide a superior automatic detection technology that employs a minimum number of pins of a connector to implement both the detection of a connection failure and the identification of an external device.
To achieve the above objects, according to a first aspect of the present invention, an automatic detection unit for identifying an external device and diagnosing connections, comprises: (a) an oblong-shaped connector having a plurality of connector pins; (b) a first identification pin group consisting of one or more connector pins arranged in the longitudinal direction at one end of the connector; (c) a second identification pin group consisting of more than one connector pins arranged in the longitudinal direction at the other end of the connector; (d) a control signal line assigned to one pin on one end of the connector; (e) means for applying a second signal level to the control signal line; (f) selection means for setting the control signal line to a first signal level to diagnose a connection with an external device and to identify the external device, and to maintain the control signal line at the second signal level on all other occasions; (g) an identification signal line along which to transmit the respective signal levels at pins in the first and the second identification pin groups; (h) diagnostic means for diagnosing the connection with an external device connected through the connector by determining whether the first signal level is detected among the second identification pin group when the control signal line is reduced to the first signal level; and (i) identification means for reading a combination of the signal levels at the pins in the first and the second identification pin groups and identifying an external device connected through the connector when the control signal line is reduced to the first signal level.
According to a second aspect of the present invention, an automatic detection unit for identifying a plurality of external devices and diagnosing connections, comprises: (a) an oblong-shaped connector provided for each of external devices, each of the connectors having a plurality of connector pins; (b) first identification pin groups provided for each of the connectors, each of the first identification pin groups consisting of one or more connector pins arranged in the longitudinal direction at one end of the connector; (c) second identification pin groups provided for each of the connectors, each of the second identification pin groups consisting of more than one connector pins arranged in the longitudinal direction at the other end of the connector; (d) control signal lines provided for each of the connectors and assigned to one pin on one end of the connector; (e) means for applying a second signal level to the control signal lines; (f) selection means for setting one of the control signal lines to a first signal level to diagnose connection with an external device and to identify the external device, and maintaining the control signal lines at the second signal level on all other occasions; (g) an identification signal line along which to transmit the respective signal levels at pins in the first and the second identification pin groups; (h) diagnostic means for diagnosing the connections with an external device connected through one of the connectors by determining whether the first signal level is detected among the corresponding second identification pin group when the control signal line is reduced to the first signal level; and (i) identification means for reading a combination of the signal levels at the pins in the corresponding first and second identification pin groups and identifying an external device connected through one of the connectors when the corresponding control signal line is reduced to the first signal level.
According to a third aspect of the present invention, an automatic detection unit for identifying a plurality of external devices and diagnosing connections, comprises: (a) an oblong-shaped connector provided for each of a plurality of external devices, each of the connectors having a plurality of connector pins; (b) first identification pin groups provided for each of the connectors, each of the first identification pin groups consisting of one or more connector pins arranged in the longitudinal direction at one end of the connector; (c) second identification pin groups provided for each of the connectors, each of the second identification pin groups consisting of more than one connector pins arranged in the longitudinal direction at the other end of the connector; (d) control signal lines provided for each of the connectors and assigned to one pin on one end of the connector; (e) means for applying a signal level to the control signal lines; (f) selection means for setting one of the control signal lines to a low signal level to diagnose connection with an external device and to identify the external device, and maintaining the control signal lines at the high signal level on all other occasions; (g) an identification signal line along which to transmit the respective signal levels at pins in the first and the second identification pin groups; (h) diagnostic means for diagnosing the connections with an external device connected through one of the connectors by determining whether the low signal level is detected among the corresponding second identification pin group when the control signal line is reduced to the low signal level; and (i) identification means for reading a combination of the signal levels at the pins in the corresponding first and second identification pin groups and identifying an external device connected through one of the connectors when the corresponding control signal line is reduced to the low signal level.
In an automatic detection unit according to the second and the third aspects, the identification signal line may be multiplexed and employed between the connectors. An automatic detection unit according to the first to the third aspects may be mounted on the planar of an information processing apparatus that employs a connector for external device expansion. In an automatic detection unit according to the second and the third aspects, a plurality of connectors are prepared to accept a plurality of external devices. The identification signal line may be multiplexed and employed for all the connectors.
According to a fourth aspect, an external device which can be connected to another apparatus through an oblong-shaped connector having a plurality of connector pins, comprises: (a) a first identification pin group consisting of one or more connector pins arranged in the longitudinal direction at one end of the connector; (b) a second identification pin group consisting of more than one connector pins arranged in the longitudinal direction at the other end of the connector; (c) a control pin assigned for a pin on one end of the connector; and (d) identification information forming means for connecting at least one pin among the second identification pin group to the control signal line, and forming identification information in accordance with the combination of the connection and disconnection between the respective pins among the first and second identification pin groups and the control signal line.
An external device according to the fourth aspect of the present invention is employed by connecting it to the automatic detection unit or to the information processing apparatus according to the first to the third aspects that has the automatic detection unit.
According to a fifth aspect, an external device which can be connected through a connector to an automatic detection unit defined in one of the first to the third aspects, comprises: (a) a first identification pin group consisting of one or more connector pins arranged in the longitudinal direction at one end of the connector; (b) a second identification pin group consisting of more than one connector pins arranged in the longitudinal direction at the other end of the connector; (c) a control pin for receiving a control signal line at one end of the connector; and (d) identification information forming means for connecting at least one pin among the second identification pin group to the control signal line, and forming identification information in accordance with the combination of the connection and disconnection between the respective pins among the first and second identification pin groups and the control signal line.
The automatic detection unit according to the first to the third aspects of the present invention provides interrelational operation by connecting an external device according to the fourth and the fifth aspects to a connector. The external device comprises: (a) a first identification pin group consisting of one or more connector pins arranged in the longitudinal direction at one end of the connector; (b) a second identification pin group consisting of more than one connector pins arranged in the longitudinal direction at the other end of the connector; (c) a control pin assigned for one pin on one end of the connector; and (d) identification information forming means for connecting at least one pin among the second identification pin group to the control signal line, and forming identification information in accordance with the combination of the connection and disconnection between the respective pins among the first and second identification pin groups and the control signal line.
The automatic detection unit according to the first aspect of the present invention accepts, with pins arranged in a connector, the first and the second identification pin groups of the external device. A control signal is input to the control pin. The signal levels at the individual pins in the first and the second identification pin groups are transmitted to the identification means and the detection means along the respective identification signal lines. The identification means and the detection means may be mounted on a single controller chip. The identification signal lines are maintained at the second signal level.
To perform automatic detection, an identification signal at the first signal level is applied to the control pin of the external device through the control signal line. When the signal level at at least one pin among the second identification pin group is the first signal level, it is assumed that there is normal contact at both ends of the oblong connector, and it is also determined that the connection for the external device is preferable. If a connection failure occurs because the connector is inserted diagonally, a control signal at the first signal level will not be transmitted from the control pin to the second identification pin group. Therefore, if all the second identification pins remain at the second signal level, the connection failure of the external device will be detected.
In the external device, the identification information expressed by the first and the second identification pin groups depends on whether the pins are connected to or disconnected from the control pin. When a control signal at the first signal level is received along the control signal line, the connections of the pins among the first and the second identification pin groups to the control signal are regarded as combinations of signal levels. Thus, the identification means can identify the external device by reading the combinations of the signal levels at the identification pins. The first signal level may be low, and the second signal level may be high.
The connector is provided for each external device that is accepted by the automatic detection unit. When, for example, a computer system mounting the automatic detection unit accepts three types of subsystems, three connectors are prepared for the connection of external devices.
According to the second and the third aspects of the present invention, an automatic detection technology is provided for a plurality of connectors. A control signal at the first signal level (low) is selectively transmitted only along the control signal line of a connector at which the connection of an external device is to be detected. In the external device connected to the selected connector, a control signal at the first signal level (low) is input to the control pin. If at least one pin in the second identification pin group indicates the first signal level (low), it is assumed that there is normal contact at both ends of the oblong-shaped connector and it is also determined that the connection for the external device is preferable. If a connection failure occurs because the connector is inserted diagonally, the control pin or the second identification pin group is apart from the connector, and a control signal at the first signal level (low) is not transmitted to the second identification pin group. Thus, when all the second identification pins maintain the second signal level (high), the connection failure at the connector is accordingly detected.
Furthermore, in the external device, the identification information is formed in accordance with a combination of the pins in first and the second identification pin groups, and depends on whether pins are connected to or disconnected from the control pin. When a control signal at the first signal level (low) is transmitted to a specific connector, the connection combination of pins in the first and the second identification pin groups in the external device connected to the connector is indicated as a combination of the signal levels. Therefore, the identification means can identify the external device connected to the connector by reading the combination of the signal levels (low/high) at the individual identification pins.
In addition, the number of signals used for identification can be reduced by multiplexing the identification signal lines among the connectors. In this invention, a specific connector can be exclusively selected by applying the corresponding control signal line to the first signal level (low), and an external device connected to that connector is both detected and identified. That is, since two or more connectors do not use an identification signal line at the same time, multiplexing of the signal line is possible.